Duplex radio machine



Dec; 4,1928. 1,64,065 .c. F. JENKINS DUPLEX RADIO MACHINE Filed Nov. 19, 1924 Patented nee 4,1928.

UNITED STATES crmatns JENKINS, or wasnmeron, nrsrnrc'r orconnmsm DUPLEX RAnIo Application filed November invention relates to the radio-photo art, and has for its principal object the transmission of photographs and synchronism on the same wave frequency or wave length.

6 With this and other objects in view, the in'-- vention consists of apparatus for transmitting and receiving radio photos and determining synchronism simultaneously, as hereinafter described and further pointed out in 10 the claims.

Referring to the accompanying drawings forming a part of this specification, in which like symbols refer to like parts in both views V Fig. 1 is atop viewof one of the station units; Fig. 2- an elevation of same; and Fig- 3 a top view of a second station unit like the unit in Fig; .1. g Y

In all three of the figures like. symbols refer to like arts, in which A is a shaft having a wideaced gear .B thereon rotated by the motor G. P On one end of the shaft A is a drum or cylinder D and on the other end a glass cylinder E. Located with its axis at right angles to the glass cylinder E is a tube F having a light sensitive cell therein. Be-

tween the sensitive cell F and the glass cylinder E is alight chopper G, on the shaft of which is a pulley H. The chopper is rotatedby a beaded chain J engaging a pulley K, on the shaft of the motor G. v

Inside the glass cylinder E is a lamp L supported in the bracket M; N is a glow lamp, the function of which is to' intermit-,

Q tently illuminate the chopper disc G.

Facing the drum D is a box P having there- 1 in a filament, a glow,- or other suitable lamp..

The lam :P is connected the radio -r'e 'ceiver R. e lightsensitive eell'F is con 40 nected to the radio sending apparatus S. The lamp N is also connected to'the radio receiver set R. a v A i The motor is rotated and its speed eon trolled by' the battery resistance and switch of the unit T.

\Vhen the motor is started the cylinders D e and E are revolved, and the light chopper G is also set in rapid rotation. The light of the small lamp L shining tl'n'ough the wall of the 5 glass eylindcrimpinges on the light 'ccll through the holes in the rotating chopper. 'lhesc holes cutting across the light with regularity produce a pulsating current of constant fre' neney. This frequency is put on the. radio roadeasting setof the sending noticeable interference.

REISSUED station S and is picked up at the receiving set i R of the distant station.

' Asboth -the chopper and the cylinders are geared to, the motor at each station, it is obvious that the chopper frequency bears 'a 00 definite relationto the rotation; of the cylnders (D and E). Therefore, if the incommg chopper frequency signals are made to light and extinguish the lamp N s on 19, 1924. Serial no. 750,801.

'the chopper at the receiving station once for 65 I each phase, i. e., each hole in the chopper at the sending station, then this intermittent illumination of the chopper G at the receiving station makes the chopper appear to stand still, if the two stations are in exact synchronism. If the stations are out of step the illuminated chopper appears to slowly rotate to theright or the left, which the proper adjustment of the rheostat T corrects. Each station unit is like the other, and on the glass cylinder E of each a transparency is put, a typewritten message, for example; A and on the cylinder D a light-sensitive paper or film is .put.

. The method of changing the light values of the picture or message put on the cylinder, and the operation of the means shown for converting the same into radio currents, and

at the receivin station putting these radio current values back into a-picture or a message, are well known, and perhaps it is not here necessary to relate them. However It might be suspected that the passing of the letters across the light-cell would make the stroboscopic" observation of synchronism ineffective, but this is not the case, and the reason it doesnot is prineipally'because the chopper frequency is so much higher than the letter (picture) frequency that there is no It will be. obvious to those skilled in the art that-many modifications are possible of the apparatus herein described and illustrated without departing from the spirit of the invention herein disclosed, which is to send and m 4 receive both a uniform frequency and an ununiform frequency at the same time and. both on the same radio wave. 7

\Vhat: I claim, is

'1. The method of electrically transmitting I and receiving visual representatihns over a single channel. which comprises varying the electrical carrier currentwvith two frequencies,'one frequency to produce the visual representationaml the other frequency to in li- 11o cate the relative timing between the sending and the receiving instruments, one of the said frequencies being constant and the other a varying frequency which modulates the constant frequency.

2. In apparatus for electrically transmitting and receiving visual representations over a single channel, means for electrically varying the carrier current in accordance with variations in intensity of fractional areas to.

predetermined areas of said representations and other means to ary the same carrier cur.-

rent to indicate synchronizing characteristics,

and the latter means having a constant frequency varied by the frequency of the former carrier current to indicate synchronizing characteristics, and the latter means having a constant frequency varied by the frequency of the former means which has a varying frequency and receiving means for detecting and utilizing both of said electrical variations.

4. In apparatus of the character described, the combination of a rotating threaded shaft with a gear thereon, the face of which is equal to the travel, and also on said shaft a cylinder bearing a light sensitive material,

and means for interrupting light adapted to.

be projected on said cylinder.

. 5. In apparatus of the character described, I

the combination ofa rotatable threaded shaft having a gear thereon, the faceof which is equal totl e. travel, and also on said shaft 2.

cylinder having a lightsensitive material and a second cylinder on said shaft having a transparency thereon.

6. In apparatus of the character described,

the combination of a rotatable threaded shaft,

having a gear-thereon, the face of which is equal to the travel, also on said shaft a cylinder bearing a second cylinder on parency thereon,

a light sensitive cell in align lightsensitive material, a said shaft h'avinga trans-' 4 ment with and in position to receive.

light changes from-the transparency,ancl a light chopper between said cylinder and light sensitive 'cell. I

7. In apparatus of the character described,

means for energizing a photo-electric-c'ell- 'modulated' transmitting circuit in accord ance with Variations in intensity of light of fractional areas of a visual representation, means responsive to another transmitting circuit for indicating the relative timing of the receiving and transmitting circuits, means located at the receiving circuits for bringing the same in perfect timed relation with the transmitting circuits.

In testimony whereof I have affixed my signature.

CHARLES FRANCIS JENKINS. 

